Anti-embolic device and method

ABSTRACT

A device for use in preventing stroke is provided. The device may include an expandable member that expands from a non-expanded configuration to an expanded configuration. The expandable member is located at a neck of a patient. An associated method is provided.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of and claims the benefit of U.S.patent application Ser. No. 14/261,565 filed on Apr. 25, 2014 andentitled, “Anti-Embolic Device and Method.” U.S. patent application Ser.No. 14/261,565 claims the benefit of U.S. Patent application Ser. No.61/816,792 filed on Apr. 28, 2013 and entitled, “External VascularCompression Device.” U.S. patent application Ser. No. 14/261,565 is alsoa continuation-in-part and claims the benefit of U.S. patent applicationSer. No. 13/859,235 filed on Apr. 9, 2013 and entitled, “Anti-EmbolicDevice and Method” which issued as U.S. Pat. No. 9,655,627 on May 23,2017. U.S. patent application Ser. No. 13/859,235 claims the benefit ofU.S. patent application Ser. No. 61/646,088 filed on May 11, 2012 andentitled, “anti-embolic neck collar.” U.S. application Ser. Nos.14/261,565, 61/816,792, 61/646,088 and 13/859,235 are incorporated byreference herein in their entireties for all purposes.

FIELD OF THE INVENTION

The present invention relates to a device and method for preventingcerebral emboli and stroke as a consequence of “emboligenic”interventions on the heart, heart valves, coronary arteries and aorta.More particularly, the present application involves a pressurizedcompression device that induces temporary noninvasive externalextravascular compression and occlusion of carotid arteries at themoment of emboligenic intervention.

BACKGROUND

Intraoperative embolic stroke is one of the most dreadful complicationsof cardiac, aortic and vascular procedures, diagnosed in 1-22% ofpatients undergoing cardiovascular surgery. Even more frequently, in upto 70% of cases, patients undergoing heart, valve, coronary arterybypass and aortic surgery experience subclinical embolic events asrecorded by transcranial Doppler and MRI. These embolic events lead tocognitive impairment and disability and have a significant impact onpatients' recovery.

The main sources of cerebral emboli and stroke in this setting residesin the heart, heart valves, thoracic aorta, and great vessels when thesestructures are intervened thereon. Even simple cardiac catheterizationwith an endovascular catheter can induce microtrauma of theatherosclerotic thoracic aorta leading to formation of embolic particleswith subsequent embolic brain injury ranging from latent ischemic focito a massive or even fatal stroke.

Multiple devices are known that attempt to prevent embolization of thecarotid arteries during endovascular and cardiac interventions by usingdifferent types of filters, deflection devices or endoluminal balloons.These anti-embolic devices, however, have not received wide acceptancein surgery of the heart, heart valves and thoracic aorta due to theircomplexity and invasive character with the risk of additional trauma tothe inner vessel wall resulting in a high risk to benefit ratio. Knowndevices require insertion of additional hardware into the arterialsystem or aorta, a procedure that is known by itself to be associatedwith all classical risks of endovascular intervention, including aorticdissection, bleeding, thrombosis, and carotid cerebral embolization andstroke. One known intra-aortic filter device that is inserted into theascending portion of the thoracic aorta via an aortic cannula to capturepotential embolic material released from the heart and aortic wallduring heart surgery was found to be quite difficult to implement andwas reported to be associated with major trauma to aortic wall and acuteaortic dissection.

Aside from introducing hardware into the patient and causing theaforementioned problems, intravascular filters are not able to captureembolus smaller than the pore size of the available devices (currently60-140 μm) resulting in cerebral microembolization. Furthermore, theplacement of the filter by itself may produce cerebral emboli. Forexample, the mere passing of a guide wire into a carotid arterygenerates approximately 40,000 microemboli, with a significantpercentage of small, less than 60 μm, particles that are not retained bystandard filters. Therefore, in spite of multiple innovations in thefield of anti-embolic devices, the problem of cerebral emboli and strokeduring cardiovascular surgery is far from being resolved. As such, thereremains room for variation and improvement within the art.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth more particularly in the remainder of the specification, whichmakes reference to the appended Figs. in which:

FIG. 1 is a front view of a patient with emboli in the heart andascending thoracic aorta with subsequent propagation of emboli into bothcarotid arteries with the source of emboli being diseased aorta, aorticvalve and the heart.

FIG. 2A is a front view of a patient with external compression of bothcarotid arteries that leads to temporary interruption of the carotidarterial flow.

FIG. 2B is a front view of a patient with external compression thatresults in divergence of flow that carries emboli to the descendingaorta and other vascular structures.

FIG. 3A is a front view of a patient with a device that is actuated inorder to achieve external compression.

FIG. 3B is a cross-sectional view of the device of FIG. 3A in anunactuated state.

FIG. 3C is a cross-sectional view of the device of FIG. 3A in anactuated state.

FIG. 3D is a front view of the device of FIG. 3A in an actuated state.

FIG. 4A is a front view of a patient with a device that features firstand second compression members in accordance with another exemplaryembodiment.

FIG. 4B is a cross-sectional view of the device of FIG. 4A in anunactuated state.

FIG. 4C is a cross-sectional view of the device of FIG. 4A in anactuated state.

FIG. 4D is a front view of the device of FIG. 4A in an actuated state.

FIG. 5 is a perspective view of a device with a transverse carotidexpandable member and two longitudinal carotid expandable members inaccordance with another exemplary embodiment.

FIG. 6A is a cross-sectional view of the device of FIG. 5 in anunactuated state.

FIG. 6B is a cross-sectional view of the device of FIG. 5 in an actuatedstate.

FIG. 6C is a front view of the device of FIG. 5 in an unactuated state.

FIG. 6D is a front view of the device of FIG. 5 in an actuated state.

FIG. 7A is a front view of a device provided for patients with short andthick necks in accordance with another exemplary embodiment.

FIG. 7B is a front view of a device provided for patients with long andthin necks in accordance with yet another exemplary embodiment.

FIG. 8A is a cross-sectional view of a neck of a patient and a deviceattached thereto in an unactuated state.

FIG. 8B is a cross-sectional view of a neck of a patient and a deviceattached thereto in an actuated state.

FIG. 9 is a cross-sectional view of a device in accordance with anotherexemplary embodiment.

FIG. 10A is a cross-sectional view of a device in an untightened statein accordance with another exemplary embodiment.

FIG. 10B is a cross-sectional view of the device of FIG. 10A in atightened state.

FIG. 11 is a front view of a patient in which the cardiac cycle is in asystole phase.

FIG. 12 is a front view of a patient in which the cardiac cycle is in adiastole phase.

FIG. 13 is a front view of a patient in whirl compressive forces areapplied to the carotid arteries during the systole phase.

FIG. 14 is a front view of a patient in which compressive forces areremoved from the carotid arteries during the diastole phase.

FIG. 15 is a front view of a patient and a system for achieving cycliccompression.

FIG. 16 is a schematic view of an alternative arrangement of the systemin which the various devices are integrated into a single device.

Repeat use of reference characters in the present specification anddrawings is intended to represent the same or analogous features orelements of the invention.

DETAILED DESCRIPTION OF REPRESENTATIVE EMBODIMENTS

Reference will now be made in detail to embodiments of the invention,one or more examples of which are illustrated in the drawings. Eachexample is provided by way of explanation or the invention, and notmeant as a limitation of the invention. For example, featuresillustrated or described as part of one embodiment can be used withanother embodiment to yield still a third embodiment. It is intendedthat the present invention include these and other modifications andvariations.

It is to be understood that the ranges mentioned herein include allranges located within the prescribed range. As such, all rangesmentioned herein include all sub-ranges included in the mentionedranges. For instance, a range from 100-200 also in ranges from 110-150,170-190, and 153-162. Further, all limits mentioned herein include allother limits included in the mentioned limits. For instance, a limit upto 7 also includes a limit of up to 5, up to 3, and up to 4.5.

The present invention provides for an apparatus and method of preventingstroke by diverting emboli from cerebral circulation. A device 26 isplaced around the neck of a patient that is non-invasive and can includea longitudinal carotid expandable member 27 and/or a transverse carotidexpandable member 32. The members 27 and 32 can be expanded from anunactuated state to an actuated state in which the members 27 and 32create an area of compression 23 at the carotid arteries 16 to preventblood how therethrough into the cerebral circulation. Emboli 17, 18 thatare formed in the patient secondary to emboligenic intervention arediverted into a descending aorta 14 and other vascular structures.

With reference to FIG. 1, a front view of a patient is shown in whichemboli 18 are transferred from the aortic arch 12 into the carotidarteries 16. The emboli 17 that are present in the carotid arteries 16can then be transferred into the cerebral circulation causing stroke ofthe patient. The emboli 18 may be fragments of atherosclerotic plaque 19of the aorta 12 that become dislodged during manipulation of theascending thoracic aorta 12. Also shown in FIG. 1 is calcification ofthe aortic valve 15 and intracardiac emboli 20 of the heart 11 that canalso be the origin of emboli 17 eventually present in the carotid artery16. The intracardiac emboli 20 may include air, gas, thrombi andatherosclerotic materials. Although all of the various emboli in theheart 11, aortic arch 12 and aortic valve 15 need not be present in allinstances, they are all shown in FIG. 1 for sake of example. Trauma tothe heart 11, aortic valve 15 and aortic structures during placement andremoval of items such as an aortic clamps, balloon valvuloplasty andelectrophysiological instruments, along with manipulations such coronaryartery bypass grafting, aortic and mitral valve replacement, catheterablation, endovascular grafting of the aorta 12, percutaneousimplantation of the aortic or mitral valves, endovascular manipulationson the aorta 12, aortic branches and the heart 11 may give rise to thepresence of emboli 17 in the carotid arteries 16. Critical moments ofthe aforementioned procedures (for example during the aortic cross clampmanipulation, aortic valvuloplasty or valve implantation, coronaryinterventions, and endovascular procedures on the aorta) may causeemboli 17 to form and, cause stroke and are referred to as “emboligenic”events.

FIGS. 2A and 2B show the disclosed method of diverging emboli 18 fromcerebral circulation by exerting external compression to form areas ofcompression 23 at the carotid arteries 16 to lead to temporaryinterruption of carotid flow. The distal carotid arteries 22 are presentdownstream from the areas of compression 23, and the proximal carotidarteries are the portions of carotid arteries 16 upstream from the areasof compression 23. Upon creation of the areas of compression 23, arelative pressure gradient and a “low-flow” condition is produced in theproximal carotid arteries 24 that prevents emboli 18 from entering thecerebral circulation. The proximal carotid arteries 24 are areas of thecarotid arteries 16 upstream from the areas of compression 23 that haveinterrupted blood flow due to the compression. Potential carotid emboli17 are diverted into the descending aorta 14 and are illustrated asemboli 21. The arrow 25 shows preferential direction of the blood flowthat carries potential cerebral emboli 17 into the descending aorta 14when the areas of compression 23 are created.

FIGS. 3A-3D disclose an exemplary embodiment of a device 26 that can beused to create the areas of compression 23 previously described todeflect emboli 17 from the carotid arteries 16 to prevent emboli in thecerebral circulation. The device 26 can be positioned on the neck of thepatient so that a pair of straps 33 and 43 extend around to the back ofthe neck of the patient and are secured to one another via hooks 44 andloops 45 that form a hook and loop type arrangement. However, it is tobe understood that other mechanisms of securing the straps 33 and 43 toone another are possible and that the disclosed arrangement is only oneexemplary embodiment. Securement of the hooks 44 and loops 45 causes thedevice 26 to be retained onto the neck of the patient. This retentionmay be loose so that the device 26 has some room to give on the neck, orthe retention may be of a tightness that firmly secures the device 26onto the neck and prevents same from moving or twisting. The device 26may be a neck collar in accordance with various exemplary embodiments.In other arrangements the device 26 may be a strap that lays on thefront of the neck of the patient, or may be made of multiple componentsthat are not directly attached to one another but are positionedproximate to the neck of the patient. The device 26 may include twosemi-oval halves that may be positioned around the neck of the patientin accordance with one exemplary embodiment. The device 26 need not becircular in shape. Even if the device 26 is not circular in shape it maystill have a central axis 56 as the central axis 56 can be located atthe center of the neck of the patient and thus may still be a centralaxis 56 of the device 26.

With reference in particular to FIG. 3B, a pair of insertion pockets 41and 42 are present on the device 26 and may be sealed at their tops andbottoms with respect to the vertical direction 55. As used herein, thevertical direction 55 may be the direction of the device 26 that isparallel to the direction of extension of the central axis 56. Strap 33may extend from the first insertion pocket 41, and strap 43 may extendfrom the second insertion pocket 42. The first insertion pocket 41 formsa cavity into which a first longitudinal carotid expandable member 27 islocated. Member 27 is shown in a deflated or unactuated state in FIG. 3Band may be made of a flexible material that can be stretched orotherwise deformed. The material making up member 27 can be nonporoussuch that member 27 is capable of being filled with gas or liquid thatenables the member 27 to expand and at the same time hold the gas orliquid therein. The pocket 41 may be made of a material that isdifferent than the material making up member 27.

The second insertion pocket 42 forms a cavity into which the secondlongitudinal carotid expandable member 46 is retained. Member 46 may beconfigured in a manner similar to member 27 and a repeat of thisinformation is not necessary. Member 46 may be completely sealed exceptfor an opening that leads into connecting tube 54. Member 46 is in anunactuated state in FIG. 3B.

A pressure source 49 is included and is placed into fluid communicationwith the first longitudinal carotid expandable member 27 by way ofpressure tubing 29 that extends through a port of member 27. A manometer30 may be included in the device 26 at some point between the member 27and the pressure source 49 in order to monitor and measure pressure inthe system. FIGS. 3C and 3D illustrate the device 26 once the pressuresource 49 is activated in order to cause the device 26 to bepressurized. The pressure source 49 may be a pump that injects air, gasor liquid, such as water, through the pressure tubing 29. Injection ofair or otherwise increasing the pressure causes the first longitudinalcarotid expandable member 27 to expand. Due to fluid communicationthrough the connecting tube 54, the second longitudinal carotidexpandable member 46 will likewise expand and the two members 27 and 46may expand at the same rate to the same size. Expansion may be in theradial direction 57 such that the expandable members 27 and 46 expandtowards the central axis 56 and away from the central axis 56. In someexemplary embodiments, the members 27 and 46 may expand in the radialdirection 57 towards the central axis 56 but not in the radial direction57 away from the central axis 56. This arrangement may be accomplishedby making portions of the expandable members 27 and 46, for example theportions facing away from the central axis 56 in the radial direction57, such that they cannot expand while the portion facing towards thecentral axis 56 are in fact expandable. The expandable members 27 and 46may be inflated to a pressure level that is above the level of thepatient's arterial pressure to achieve temporary interruption of thecarotid blood flow. Both the left and right carotid arteries 16 can becompressed at the same time.

Additionally or alternatively, the insertion pockets 41 and 42 couldhave portions that are made of different materials so that the partsfacing the central axis 56 in the radial direction 57 are expandablewhile the parts facing away from the central axis 56 in the radialdirection 57 are not expandable. The expandable members 27 and 46 areelongated in the vertical direction 55, which is the same direction asthe central axis 56. However, it may be the case that upon expansion ofthe expandable members 27 and 46 from the unactuated to the actuatedstates the expandable members 27 and 46 do not expand in the verticaldirection 55.

The exemplary embodiment of the device 26 in FIGS. 3A-3D does notinclude a transverse carotid expandable member 32 but instead includesonly two expandable members 46. The device 26 may be placed onto thepatient so that the first longitudinal carotid expandable member 27overlays the carotid artery 16 such that the carotid artery 16 islocated between the central axis 56 and the member 27 in the radialdirection 57. The second longitudinal carotid expandable member 46 maybe laid on top of the other carotid artery 16 such that the secondcarotid artery 16 is likewise between the member 46 and the central axis56 in the radial direction 57. Expansion forces of the expandablemembers 27 and 46 may be imparted onto the carotid arteries 16 so thatthey are compressed thus forming the areas of compression 23 aspreviously discussed. The pressure in the expandable members 27 and 46may be set so as to exceed the patient's systemic pressure to achieveadequate compression of the carotid arteries 16 to have a transient“no-flow” effect. In some arrangements the pressure of the members 27,32 and/or 46 may exceed the patient's systemic pressure by 10-20 mm Hg,or up to 30 mm Hg or higher in accordance with certain exemplaryembodiments. In some embodiments the expandable members 27, 32 and 46are inflated to a pressure exceeding the patient's systemic pressure byat least 10 mm Hg. Once the “emboligenic” part of the procedure iscompleted, the pressure in members 27 and 46 may be released in order toestablish carotid arterial flow.

Another exemplary embodiment of the device 26 is illustrated in FIGS.4A-4D. The device 26 in this exemplary embodiment also functions tocompress the carotid arteries 16 to create the areas of compression 23.The device 26 includes a first insertion pocket 41 and a secondinsertion pocket 42 but lacks first and second longitudinal carotidexpandable members 27 and 46. Instead a first compression member 52 islocated within the first insertion pocket 41, and a second compressionmember 53 is located within the second insertion pocket 42. Thecompression members 52 and 53 are not expandable but may be made of amaterial, such as foam, that can be compressed and then can subsequentlyexpand back into its original shape. The compression members 52 and 53may alternatively be made of a material that does not exhibit any giveupon the application of forces thereto that would be encountered in aprocedure of the type described herein. The compression members 52 and53 may be elongated in the vertical direction 55 and may have a convexshape that faces the central axis 56. The shape of the compressionmembers 52 and 53 at their surfaces that face away from the central axis56 in the radial direction 57 may be different than those that facetowards the central axis 56.

The device 26 may include a transverse carotid compression section 31that is located outward from the compression members 52 and 53 in theradial direction 57 from the central axis 56. A transverse carotidexpandable member 32 may be held by the section 31 and can have an arelength about the central axis 56 that extends beyond both of thecompression members 52 and 53. The transverse carotid expandable member32 has a height in the vertical direction 55 that is the same as, largeror smaller than the height of the compression members 52 and 53 in thevertical direction 55. The member 32 is made of a material that willhold air, gas or liquid such that it can be expanded upon theapplication of fluid thereto. The member 32 has a single port that is influid communication with the pressure tubing 29. Application of pressureto the member 32 will cause the member 32 to expand as shown for examplein FIGS. 4C and 4D. In other embodiments, the compression members 52 and53 can be removed and not present so that only the expandable member 32is present to compress the carotid arteries 16.

The transverse carotid compression section 31 can be arranged so thatall of it is expandable or so that only a portion of it expands as themember 32 expands. Boundary lines 50 and 51 may demarcate areas of thetransverse carotid compression section 31 that can expand from thosethat cannot expand. For example, the portion of section 31 radiallyoutward from the boundary lines 50 and 51 may not be capable ofexpansion while the portions of section 31 radially inward from boundarylines 50 and 51 are capable of stretching and thus expanding orcontracting. This arrangement may cause expansion only, or primarily, inthe radially inward direction upon expansion of the expandable member32. In other embodiments, the section 31 is made of the same materialand exhibits expansibility such that it generally expands in alldirections equally. The expandable member 32 may be arranged so that itdoes not lengthen in the vertical direction 55 upon expansion, or insome arrangements only minimally expands in the vertical direction 55when actuated.

Placement of the device 26 onto the patient may result in the firstcompression member 52 overlaying the carotid artery 16 so that thecarotid artery 16 is between compression member 52 and the central axis56 in the radial direction 57. The second compression member 52 will bearranged so that it overlays the second carotid artery 16 causing it tobe between the second compression member 52 and the central axis 56 inthe radial direction 57. The expandable members 27, 32 and 46 may belocated at the neck of the patient such that they are secured to theneck or otherwise proximate the neck. The expandable members 27, 32 and46 need not be in direct contact with the neck of the patient but onlylocated near the neck of the patient. Application of pressure via thepressure source 49 causes the transverse carotid expandable member 32 toexpand in the radial direction 57. This inward radial expansion causesthe compression members 52 and 53 to move inwards and be urged againstthe carotid arteries 16. The positioning and configuration of themembers 52 and 53 function to impart compressive forces onto the carotidarteries 16 when the device 26 is pressurized thus resulting in thecreation of the areas of compression 23. The other components of thedevice 26 may be made as those previously described and a repeat of thisinformation is not necessary.

Although described as lacking first and second longitudinal carotidexpandable members 27 and 46, an alternative arrangement may be made inwhich these members 27 and 46 are present. In such an arrangement, theexpandable members 27 and 46 may expand in order to press thecompression members 52 and 53 towards the carotid arteries 16.

An alternative exemplary embodiment of the device 26 is illustrated withreference to FIG. 5 in which both a pair of longitudinal carotidexpandable members 27 and 46 are present along with a transverse carotidexpandable member 32. A pair of compression members 52 and 53 may bemissing from this embodiment, or they may be present in certainarrangements. This exemplary embodiment includes additional pressuretube lines 47 and 48 that are separate from pressure tubing 29 thatactuates the transverse carotid expandable member 32. Pressure tubelines 47 and 48 provide pressure to the first and second longitudinalcarotid expandable members 27 and 46 so that these members 27 and 46 canbe expanded at different rates, amounts, and/or times than expandablemember 32. This flexibility provides selective pressure adjustmentsbetween the transverse carotid expandable member 32 and the pair oflongitudinal carotid expandable members 27 and 46. This feature willprovide an option to decrease or completely eliminate the degree ofcircumferential neck compression when selective inflation of the twolongitudinal carotid expandable members 27 and 46 is adequate.Conversely, if inflation of members 27 and 46 does not lead tosufficient reduction of the carotid flow, an additional inflation of theexpandable member 32 would allow one to achieve the desired effect bycombining the effect of pressure created in all of the members 27, 46and 32.

The preferred method of carotid artery 16 compression in this case willbe an initial inflation of members 27 and 46, followed by inflation ofmember 32 when necessary. The degree of interruption of the carotid flowin this and other embodiments can be checked by the data of carotidDoppler, trans-cranial Doppler, pulsation of the temporal arteries andother techniques of assessment of the carotid and cerebral perfusion.The other components of the device 26 are the same as those previouslydisclosed with respect to other embodiments and a repeat of thisinformation is not necessary.

An alternative exemplary embodiment of the device 26 is disclosed withreference to FIGS. 6A-6D. The embodiment disclosed is similar to thatpreviously disclosed with respect to FIG. 5 and a repeat of the featuresand functionality that are similar between the two need not be repeated.The pressurization of the members 27, 32 and 46 are different in thatthe second pressure tube 47 feeds into the first longitudinal carotidexpandable member 27, and in that the third pressure tube 48 suppliesthe second longitudinal carotid expandable member 46 to allow themembers 27 and 46 to be pressurized independently from one another. Inthis regard, one can apply more or less pressure to member 27 thanmember 46 so that compression of the carotid arteries 16 can be moreprecisely controlled. The transverse carotid expandable member 32 issupplied by pressure tubing 29 and is independent from the expansion ofmembers 27 and 46 such that it can be pressurized to a greater or lesserextent than members 27 and 46. The manometer 30 may be capable ofmeasuring pressures in all of the lines 29, 47 and 48 so that theirindividual pressures can be monitored. In use, one may adjust thepressures in members 27 and 46 first, then subsequently if needed onemay apply pressure into member 32 to cause its expansion so thatadequate compression of the carotid arteries 16 is realized.

The ports for the pressure lines 47 and 48 may be located at the bottomof the expandable members 27 and 46 in the vertical direction 55.However, the ports for pressure lines 47 and 48 need not be in thedisclosed locations in accordance with other exemplary embodiments andmay be above the transverse carotid compression section 31 or at thesame location as the section 31 in the vertical direction 55 in otherexemplary embodiments. The insertion pockets 41 and 42 althoughdescribed as being sealed may have an opening into which the expandablemembers 27 and 46 may be removed and into which first and/or secondcompression members 52 and 53 may be inserted so that the device 26 canfunction with the compression members 52 and 53 and transverse carotidexpandable member 32 as previously discussed.

The arrangement of the device 26 in FIGS. 6A-6D thus includes a pair oflongitudinal carotid expandable members 27 and 46 along with atransverse carotid expandable member 32. With reference to FIG. 6B, theboundary lines 50 and 51 may be located at the boundaries of the straps33 and 43 and the transverse carotid compression section 31. The lengthsof the members 27 and 46 in the vertical direction 55 are each longerthan the length of the member 32 in the vertical direction 55, and thearc length of the member 32 is larger than the arc lengths of themembers 27 and 46 combined. The transverse carotid expandable member 32may have an arc length that extends up to 65% of the circumferentialdistance about the central axis 56. In this regard, the member 32 mayhave an arc length that is up to 234 degrees about central axis 56. Thecircumferential distance about the central axis 56 may also be thecircumferential distance about the neck of the patient when the device26 is worn by a patient and thus these two terms can be interchangeablewhen discussing the arc length of the member 32. In other exemplaryembodiments, the arc length of the member 32 may be from 50-65% (180degrees-234 degrees) about the circumference of the neck of the patient,from 25%-50% (90 degrees-180 degrees) about the circumference of theneck of the patient, or from 15%-25% (54 degrees-90 degrees) about thecircumference of the neck of the patient. In yet other exemplaryembodiments, the member 32 may extend 360 degrees completely about thecentral axis 56/neck of the patient.

The members 27 and 46 are closer to the central axis 56 in the radialdirection 57 than the member 32 is to the central axis 56. Comparison ofFIGS. 6C and 6D demonstrate that the lengths of the members 27, 32 and46 do not increase in the vertical direction 55, or in the arc lengthdirection, upon moving from the unactuated orientation to the actuatedorientation or only slightly expand in these directions upon actuation.The majority of the expansion may be in the radial direction 57 eithertowards the central axis 56 or away from the central axis 56 or acombination of the two. In other arrangements, however, expansion of themembers 27, 32 and 46 may result in equal expansion in all directions.As previously stated, various components of the device 26 in FIGS. 6A-6Dmay be arranged and function in a manner similar to those as previouslydiscussed and a repeat of this information is not necessary.

FIGS. 7A and 7B disclose modifications of the geometry of the members 27and 46 with respect to the geometry of the transverse carotid expandablemember 32 which is the same in both FIGS. 7A and 7B. The differentgeometries for members 27 and 46 may be due to variations of neckanatomy in each patient. In patients with a short and large neck theembodiment in FIG. 7A may be employed that has longitudinal carotidexpandable members 27 and 46 that are bigger and more round to achievemore efficient carotid compression. The length of each one of themembers 27 and 46 in the vertical direction 55 may be less than thelength of the member 32 in the vertical direction 55 both when all ofthe members 27, 32 and 46 are unexpanded, and when all of the members27, 32 and 46 are expanded. In patients with a long and thin neck thepreferred embodiment comprises the members 27 and 46, as shown in FIG.7B, that are more oval and narrow for the same reason of more efficientcarotid compression to account for the differences in neck geometries ofpatients. The lengths of each of the members 27 and 46 in the verticaldirection 55 is longer than the length of the member 32 in the verticaldirection 55 both when all of the components 27, 32 and 46 areunactuated and when they are all actuated.

FIGS. 8A and 8B demonstrate the method of use and the effect ofinflation of the device 26 resulting in external compression of bothcarotid arteries 16, leading to transient interruption of carotid flow.These two figures demonstrate the anatomic relationship of the device 26to both carotid arteries 16 and surrounding structures 34, 35, 36, 37and 40. The carotid arteries 16 are bordered by neck muscles 36,esophagus 35, trachea 34 and fat tissues 40. These structures provide aprotective cushion, minimizing the risk of carotid injury duringexternal compression. In fact, an external compression of carotidarteries 16 in this setting would lead to significantly lower risk ofinjury to carotid intima than intravascular carotid occlusion with theballoon or umbrella devices used for cerebral protection in patientsundergoing carotid stenting. The longitudinal carotid expandable members27, 46 are positioned along the course of both carotid arteries 16 onthe neck.

The exemplary embodiment of the device 26 may be any one of thosepreviously disclosed that lacks a transverse carotid expandable member32. However, it is to be understood that this is just one example andthat other devices 26 that include member 32 can function in a similarmanner to the device 26 disclosed in FIGS. 8A and 8B. As shown in FIG.8A, one of the longitudinal carotid expandable members 27 is placedalong the course of one of the carotid arteries 16, and the otherexpandable member 46 is placed along the course of the other carotidartery 16. The lumen of both carotid arteries is compressed between theinflated bladders 27 and 46 anteriorly (outward in the radial direction57) and the cervical spine 37 posteriorly (inward in the radialdirection 57). Actuation of the members 27 and 46 cause the members tomove radially inward and compress fat tissue 40 that is immediatelyadjacent the device 26. The expandable members 27 and 46 are shownmoving in the radial direction 57 inward of portions of the trachea 34and neck muscles 36 so that portions of the expandable members 27 and 46are closer to the central axis 56 in the radial direction 57 thanportions of the trachea 34 and neck muscles 36. Full expansion of theexpandable members 27 and 46 may result in inward radial movement sothat they are not radially closer to the axis 56 than any portion of theesophagus 35. However, other embodiments are possible in which at leastsome portion of the expandable members 27 and 46 are closer to thecentral axis 56 than a portion of the esophagus 35.

The soft tissues such as the fat tissues 40, neck muscles 36, esophagus35 and trachea 34 around carotid arteries 16 provide a smooth cushionassuring adequate protection against carotid trauma. Expansion of themembers 27 and 46 causes the areas of compression 23 to restrict bloodflow through the carotid arteries 16 which leads to transientinterruption of carotid flow. The trachea 34 and esophagus 35 are notclosed or restricted upon actuation of the expandable members 27 and 46due to the placement and specific configuration of the expandablemembers 27 and 46. However, in some arrangements some degree ofrestriction of the trachea 34 and/or esophagus 35 may occur when theexpandable members 27 and 46 are expanded. It may be advisable, however,to obtain carotid Duplex scan in all patients planned for this procedureto rule out significant atherosclerotic disease of these vessels 16. Ifthe patient is found to have severe carotid disease, the risk ofdislodging the carotid plaque due to carotid compression should beweighed against the risk of stroke associated with the maincardiovascular intervention.

The divergence of potential cerebral emboli 17, 18 and prevention ofstroke can be achieved by a noninvasive safe method that involvesexternal compression of the carotid arteries 16. The method and device26 disclosed do not require puncture of the skin or arteries and do notnecessitate the use of endovascular devices. The device 26 and disclosedmethod allow for the divergence of emboli 17 and 18 of all sizes,including those microscopic particles that are too small to be trappedwith the known intravascular filters.

Various types of mechanisms capable of compressing the carotid arteries16 can be included in the device 26 in addition to or alternatively tothose previously discussed. For example, the device 26 can be suppliedwith different carotid compression mechanisms, including different formsof longitudinal bladders, cuffs, compression pads or inserts with thesame effect of carotid compression to the point of transientinterruption of carotid flow. The fluid provided to pressurize theexpandable components of the device 26 from the pressure source 49 maybe a liquid substance in some embodiments. Fluid that is a liquid may beused in the device 26 to effect pressurization and more uniformconstriction of the carotid arteries 16 than gas or air fluid becauseliquid is more non-compressible at the operating range of pressures.Liquid fluid in the members 27, 32 and 46 may more directly transmitpressure to the carotid area than gas or air fluid.

Further, although shown as employing a single pressure source 49, it isto be understood that multiple pressure sources 49 may be used. Forinstance, the transverse carotid expandable member 32 may be pressurizedby a first pressure source 49 such as a pump, while a second source ofpressure 49 is included in the device 26 to provide pressure to the twolongitudinal carotid expandable members 27 and 46.

A monitoring system 58 may be included with the device 26 to assure asafe, adequate, easily manageable and controllable compression ofcarotid vessels 16. The monitoring system 58 may comprise Dopplerultrasound, Doppler probe, oscillotonometry, electroencephalography,transcranial Doppler, cerebral oximetry and/or other techniques. Thedevice 26 may be actuated to such a degree that the two areas ofcompression 23 formed completely stop the flow of blood into the distalcarotid artery 22, or to an extent that partial flow of blood passesthrough the areas of compression 23 and into the distal carotid artery22 and cerebral circulation.

The device 26 provided is a noninvasive and precise apparatus with anoption of assessing a degree and an effectiveness of an interruption ofthe carotid flow by the optional inclusion of a monitoring system 58.The device 26 assures a uniform and reproducible interruption of thecarotid flow bilaterally minimizing the risk of trauma to the carotidartery wall and subsequent cerebral emboli 17. An alarm system 59 can beincluded in the device 26 that is triggered by excessive or lengthycompression of the carotid arteries 16. The alarm system 59 may be apart of the monitoring system 58 or may be a different component that isnot part of the monitoring system 58. The alarm system 59 may thusmeasure the time of compression, and the magnitude of compression.Constant monitoring of carotid 16, systemic arterial and device 26pressures with pressure in the device 26 exceeding only slightly thepressure in the arterial system may be conducted to ensure safeoperation and use at the disclosed device 26. The device 26 provides anoninvasive compression apparatus that does not require the insertion ofintravascular devices.

With reference now to FIG. 9, an alternative exemplary embodiment of thedevice 26 is illustrated. Here, the device 26 lacks an expandable member27, 32, or 46 and includes a compression member 52. The particulararrangement of FIG. 9 also includes a second compression member 53. Thecompression members 52, 53 are located within and held by first andsecond insertion pockets 41 and 42. The compression members 52 and 53may be as previously described and a repeat of this information is notnecessary. The compression members 52, 53 may be referred to ascompression members because they function to compress the carotidarteries 16. The compression members 52, 53 may themselves becompressible such that they can be deformed when force is appliedthereto to be compressed and hence smaller. When the force is removedthe compression members 52, 53 can spring back to their non-compressedstate. However, in some arrangements the compression members 52, 53 arenot compressible themselves at all and maintain the same size and shapewhen force is applied. The compression members 52, 53 still function tocompress the carotid arteries 16 even when they themselves are notcompressible. The compression members 52, 53 function without be ngexpanded by the pressure source 49. The device 26 of FIG. 9 lacks apressure source 49 and no components of the device 26 are expandable.

A strap 33 extends from the boundary line 50 and has hooks 44 disposedthereof. Strap 43 extends from boundary line 51 and has loops 45 locatedon one surface thereof. The straps 33, 43 extend circumferentiallyaround the central axis 56 and may surround the central axis 56 up to240 degrees in some exemplary embodiments. The straps 33, 43 areadjustable in that they can be unattached from one another and thenreengaged such that the points of contact between the hooks 44 and theloops 45 are changed. This change causes the relative size of the device26 in the radial direction 57 to either increase to relive pressure onthe neck of the patient, or decrease to increase the amount of pressureon the neck of the patient so that the compression members 52 and 53apply greater pressure to the carotid arteries 16.

Although shown and described as a pair of straps 33, 43 it is to beunderstood that as used herein the term “strap” is broad enough toinclude a pair of straps, a single strap, or any other tighteningmechanism. If a single strap is present it will extend from boundaryline 50 to boundary line 51 and can be adjustable to increase pressuresupplied by the device 26 to the neck of the patient, or non-adjustablesuch that it may function to hold the device 26 to the neck of thepatient while some other mechanism functions to apply pressure to thecompression members 52 and 53.

Another exemplary embodiment of the device 26 is shown in FIGS. 10A and10B. The device 26 includes a pair of compression members 52, 53 thatare held by pockets 41 and 42. The compression members 52, 53 may applypressure to the carotid arteries 16 and in this regard need to directlycontact the skin of the neck of the patient. Instead, the insertionpockets 41 and 42 directly contact the skin of the neck of the patient,and the compression members 52, 53 apply pressure to the carotidarteries 16 by exerting force through the insertion pockets 41, 42 andinto the neck of the patient. The embodiment in FIGS. 10A and 10B lacksa source of pressure and the device 26 does not have an expandablemember.

Strap 33 extends from boundary line 50 of the device 26 and is longerthan strap 43 that extends from boundary line 51. A lock and adjustmentclip 60 is attached to the end of strap 33 and this attachment may be apermanent attachment. Strap 43 is not attached to the lock andadjustment clip 60 in FIG. 10A. The health care provider may place thedevice 26 around the neck of the patient so that the compression members52, 53 overlay the carotid arteries 16 of the patient. The strap 43could be moved through the lock and adjustment clip 60 and securedthereto so that the strap 43 is attached to the strap 33 to cause thedevice to be held onto the neck of the patient. However, the tighteningof the strap 43 relative to strap 33 may be loose such that thecompression members 52, 53 do not apply pressure to the carotid arteries16.

When compression of the carotid arteries 16 is desired, the health careprovider may adjust the strap 43 relative to the lock and adjustmentclip 60 as shown for instance in FIG. 10B. The health care provider canmove a desired amount of the length of strap 43 through the lock andadjustment clip 60 and then lock the strap 43 to the lock and adjustmentclip 60 so that it does not move relative thereto. This adjustmentcauses the size of the device 26 in the radial direction 57 to decrease,relative to the size in FIG. 10A, and forces the compression members 52,53 against the carotid arteries 16 to compress the carotid arteries 16.The straps 33, 43 thus function to not only hold the device 26 onto theneck of the patient, but to also apply the pressure necessary forcompressing the carotid arteries 16.

Other arrangements of the device 26 are possible. For example, thestraps 33 and 43 can be located on the device 26 to hold the device 26onto the patient but not to provide force that causes the compressionmembers 52, 53 to be pressed against the carotid arteries 16. The device26 may lack any members that are expandable, and thus may lack apressure source 49. A belt or other mechanism can be wrapped around thecompression members 52, 53 and may be tightened so that force from thistightening is transferred to the compression members 52, 53 so that theyin turn be urged against the carotid arteries 16 to close the carotidarteries 16.

A method for reducing or totally preventing cerebral emboli will now bediscussed. A brief compression of carotid arteries 16 by way of a device26 may be performed first to assure adequate position of the deviceleading to reduction or interruption of carotid flow or pulse asassessed by carotid Doppler, a pressure gauge, percutaneous cerebraloximetry or transcranial Doppler.

Once an adequate position of the device 26 is confirmed, the pressure inthe carotid compression components (27, 32 and 46) is released and theapparatus 26 is ready for use. The device 26 is inflated to the pressureexceeding patient's systemic pressure just before proceeding with theemboligenic part of the procedure. Adequate compression of carotidarteries 16 will lead to physiological reduction of flow throughvertebral arteries leading to further divergence of blood and emboliaway from all cerebral vessels and toward more distal arteries, thusdecreasing the risk of stroke.

The pressure in the device 26, and thus to the expandable components 27,32 and 46 is released after the emboligenic procedure is completed aftera full washout of potential emboli 20, 18 from the heart 11 and thoracicaorta 12. The expandable components 27, 32 and 46 are deflatedapproximately 30-90 seconds after the emboliogenic procedure iscompleted after a full washout of potential emboli 20, 18 from the heart11 and thoracic aorta 12. The pressurization of the device 26 can berepeated any time and on multiple occasions when the emboligenicintervention is contemplated.

Should the physician or physician's assistant forget to release carotidcompression timely, an alarm would go off and the pressure would bereleased spontaneously to avoid undue interruption of the cerebral flow.The alarm and deflation could be overridden by the physician whenclinically indicated. The alarm may be sounded by the alarm system 59,and the deflation may be activated by the pressure source 49 and/or thealarm system 59 and/or the monitoring system 58. The device is deflatedapproximately 30-90 seconds after the emboligenic procedure is completedafter a full washout of potential emboli from the heart and thoracicaorta.

The central axis 56 may be present even when the device 26 is notconfigured with straps 33, 43 to form a generally circular member whenviewed from the top as for example in FIG. 6A. In some embodiments ofthe device 26, a circular member is not formed when viewed from the topby the straps 33, 43. For instance, the straps 33, 43 may be missingsuch that the section 31 is attached to sides of a bed or otherwisesecured so that the device 26 is located at the neck of the patient. Insuch instances, the central axis 56 is still present. The central axis56 may be located at a location within the neck of the patient, forexamples shown with reference to FIGS. 8A and 8B. This location may beat the spinal column 37 of the patient, or may be at the center of theneck of the patient, it is to be understood that various embodiments ofthe device 26 exist in which the device 26 does not wrap completelyaround the neck of the patient but instead only wraps around a portionof the neck of the patient less than 360 degrees fully about the neck ofthe patient.

The device 26 may be provided so that no portion of the device 26 isinside of the patient and all of the device 26 is located outside of thepatient. The method may be performed such that nothing is insertedinside of the patient to deflect the emboli 18. In this manner, thedevice 26 is not an invasive device as no portion is located within thecarotid arteries 16 or under the skin or otherwise inside of thepatient. The device 26 may be arranged so that it contacts the neck ofthe patient but not other parts of the patient such as the head of thepatient, the arm of the patient, the leg of the patient, the chest ofthe patient, or the back of the patient. The device 26 may function tocompress the carotid arteries 16 but not any other arteries of thepatient. In this regard, the only arteries that are compressed by thedevice 26 are the carotid arteries 16.

Information Added in Continuation-in-Part Application

The odds of embolic particles 18 and 20 breaking loose and migratinginto cerebral vessels 16 are minimal when the heart 11 is relaxed and/ornot ejecting blood. This is observed in patients on cardiopulmonarybypass when the heart 11 is not filled with blood and is unable to ejector is in diastolic arrest. Diastolic arrest is a condition when theheart 11 is not contracting while being totally relaxed (diastole).Echocardiography in this situation will frequently show particles of airthat are enclosed in the heart chambers. When the heart 11 is filledwith blood and starts contracting, these particles 18 and 20 startmoving and ultimately get ejected into the aortic arch 12 and itsbranches leading to cerebral emboli and stroke. Transcranial Dopplerevaluation of middle cerebral arteries at this stage of the proceduremay detect an appearance of high intensity microembolic signals (HITS)that confirm the process of embolization of cerebral arteries occurringwith each cardiac contraction and ejection of blood into the aorta 12.

These particles 18, 20 may stay trapped inside the heart 11, pulmonaryveins, and aorta 12 for a significant amount of time even afterresumption of cardiac ejection. The embolic events may occurs minutes oreven hours after “emboligenic” intervention. Each cardiac contractionand ejection of blood from the left ventricle in this setting will beassociated with the release of multiple embolic substances 18, 20 fromthe heart 11, aortic valve 15 and ascending aorta 12 into systemiccirculation and the carotid arteries 16, leading to embolic stroke.

A system 70 may be provided to temporarily block or decrease blood flowto the carotid arteries 16 and the brain at the moment of cardiaccontraction (systole) when the risk of embolization is maximal, but toallow for reconstitution of the carotid blood flow when heart 11 relaxes(diastole). This approach may decrease the amount of particles 17reaching the brain with each systolic ejection of the heart 11 by virtueof their divergence away from the brain into the more distal branches ofthe aorta 14. Additionally, this approach may provide an adequate bloodflow to the brain during cardiac diastole—the phase of cardiaccontraction know to be essential for optimal cerebral blood flow. Thefact that the duration of cardiac diastole is significantly longer thatthe duration of systole allows assuring adequate blood supply to thebrain in spite of brief “systolic” interruptions of cerebral arterialinflow.

The compression d vice 26 may be employed in the system 70 that monitorsa cardiac cycle of a heart 11 of a patient and synchronizes thecompression device 26 with the cardiac cycle so that the compressiondevice 26 applies a compressive force 72 during some phases of thecardiac cycle and does not apply the compressive force 72 during otherphases of the cardiac cycle. The provided apparatus and method preventsstroke by diverting emboli 18, 20 from cerebral circulation whileproviding adequate flow to the brain. The pulsatile compression deviceis placed around the neck of a patient so as to be applied externally tothe patient. The device 26 is non-invasive and can include alongitudinal carotid pulsatile expandable member 27 and/or a transversecarotid pulsatile expandable member 32, or any of the compressionmembers and arrangements as previously discussed. The device 26 mayapply compressive force 72 to the carotid arteries 16 during a systolephase of the cardiac cycle to prevent blood flow and emboli 18, 20 fromentering the brain and causing stroke. In order to assure adequate bloodflow to the brain through the carotid arteries 16, the compressive force72 may be removed during the diastole phase, and if needed in somearrangements early systole, when the heart is relaxed or not yetejecting and the risk of ejection of emboli 20 into the aorta 12 andcarotid arteries 16 is minimal.

With reference again to FIG. 1, emboli 17, 18 and 20 may be present inthe circulatory system through the previously listed conditions andprocedures which may find their way through the carotid arteries 16 andinto cerebral circulation. The intracardiac emboli 20 may include air,gas, thrombi and atherosclerotic materials. FIG. 11 shows the heart 11in a systole phase of the cardiac cycle in which the heart 11contracts/squeezes and blood is pumped therefrom. The contractions ofthe heart 11 (systole) will lead to opening of the aortic valve 15 andejection and washout of emboli 20 into the aorta 12 with the most directanatomical target being the carotid arteries 16 and the brain. Emboli 17will thus be pushed into and through the carotid arteries 16 when theheart 11 contracts in the systole phase of the cardiac cycle.

FIG. 12 shows the heart 11 in a diastole phase of the cardiac cycle inwhich the heart 11 muscles relax and blood fills the chambers of theheart 11. As shown, the heart 11 expands from the systole phase duringcardiac relaxation and blood ejection is significantly decreased or eventotally absent along with washout of intra-cardiac particles 20 from theheart 11 and aorta 12.

FIGS. 13 and 14 show an exemplary embodiment of the disclosed method ofdiverging emboli 17, 18, 20 from cerebral circulation by exertingpulsatile external compression to form areas of compression 23 in whichthe carotid arteries 16 are narrowed and either completely or partiallyclosed. Blood flow may be limited in that it is completely preventedfrom moving through the carotid arteries 16, or so that it is partiallylimited in moving through the carotid arteries 16 such that some bloodflows through the carotid arteries 16 but not as much as would be thecase through normal circulation if no compression device 26 withcompressive force 72 were present. This narrowing of the carotidarteries 16 leads to a temporary pressure gradient and the interruptionof carotid flow during cardiac systole and ejection. This compressionmay be synchronized with the phases of the heart cycle in such a waythat the areas of compression 23 are formed during cardiac systole, orthe part of systole when the heart 11 ejects. The compression is alsosynchronized in which it is partially or completely released duringdiastole. The actuation of the device 26 may be triggered throughmonitoring the cardiac cycle by a cardiac monitoring device 80 such asEKG machines, arterial pressure waveform devices, or pulse oximetrydevices.

Creation of the areas of compression 23 cause the emboli 18 to bediverted from the carotid arteries 16 and into the descending aorta 14as previously discussed. Release of the compressive three 72 so that theareas of compression 23 are removed is shown in FIG. 14. The release ofpressure on the carotid arteries 23 during cardiac relaxation is notassociated with ejection of emboli 20 from the heart and embolization ofthe carotid arteries 16. The aortic valve 15 is closed. It may be thecase that there is a small amount of floating particles 18 in theascending aorta 12. However, the chance of migration into the carotidarteries 16 in the absence of cardiac ejection, that is when the aorticvalve 15 is open and blood is being pumped from the heart 11, isminimal. The entire process of creating the compression areas 23 andreleasing the compression to remove the compression areas 23 can berepeated (cycled) in concert with the cycles of systolic contraction anddiastolic relaxation in the cardiac cycle. The cycling process can bestarted before the surgical procedure or at some point during thesurgical procedure that is likely to form emboli 18, 20. Also, thecirculatory system can be monitored and once the presence of emboli 18,20 is detected the compression/removal cycle can be started.

FIG. 15 shows a system 70 that may be used to execute thecompression/removal cycle. The system 70 may include a compressiondevice 26 that can be arranged or provided in any manner as previouslydiscussed. An actuation device 74 is present, and is in communicationwith the compression device 26 to cause the compression device 26 toactuate. The actuation device 74 may cause the compression device 26 tomove from an actuated state to an unactuated state, and in somearrangements may cause the compression device 26 to move to a partiallyactuated state. The actuation device 74 may be a pressure source 49 insome exemplary embodiments. The actuation device 74 may supply fluid,such as air, to the first and second longitudinal carotid expandablemembers 27, 46 in order to inflate them, and may withdrawal the fluidwhen compression forces 72 are no longer desired by deflating themembers 27, 46. Here, the actuation device 74 may withdraw air from theexpandable members 27, 46, or a valve on the expandable members 27, 46may be opened to deflate them in order to remove the compressive forces72. The actuation device 74 may be separate from the compressive device26 or may have one or more components attached to and part of thecompressive device 26.

In other arrangements of the system 70, for example when the compressiondevice 26 is configured as shown in FIGS. 9 and 10, the actuation device74 may have a linear actuator or motor that is attached to the strap 43for pulling or pushing the strap 43 in one or more directions togenerate the compressive forces 72 and to remove the compressive forces72. The actuation device 74 need not be a separate component from thecompression device 26, but may be integrally formed with the compressiondevice 26 such that they are carried together as essentially onecomponent.

The system 70 may include a cardiac monitoring device 80 that monitorsthe cardiac cycle of the heart 11. The cardiac monitoring device 80 canbe an electrocardiogram (EKG) machine, a blood pressure waveform device,an arterial pressure waveform device, a cardiac pacing device, a pulseoximetry device or another mechanism to ascertain when the heart 11 isin a systole phase and a diastole phase. In other arrangements thecardiac monitoring device 80 may be carotid Doppler, trans-cranialDoppler, pulsation of the temporal arteries, Dopplerography,oscillotonometry, oximetry and other techniques of assessment of thecarotid and cerebral perfusion. The cardiac monitoring device 80 maymonitor the heart or any portion of the circulatory system or otherportion of the patients anatomy in order to ascertain data relevant tothe cardiac cycle.

The cardiac monitoring device 80 may be in communication with asynchronization device 82. Data may be transferred from the cardiacmonitoring device 80 to the synchronization device 82, and in somearrangements data from the synchronization device 82 may be transferredto the cardiac monitoring device 80. The synchronization device 82 maybe in communication with the actuation device 74 such that data from thesynchronization device 82 is communicated to the actuation device 74.Likewise, the actuation device 74 may in turn communicate back to thesynchronization device 82 in some arrangements. The synchronizationdevice 82 may obtain data from the cardiac monitoring device 80 relevantto the phases of the cardiac cycle the heart 11 is experiencing. Usingthis data, the synchronization device 82 may match the creation andremoval of the compressive force 72 to match the desired phases of thecardiac cycle. The synchronization device 82 may deliver a command tothe actuation device 74 to cause the actuation device 74 to actuationthe compression device 26 when desired. Likewise, the synchronizationdevice 82 may deliver a command to the actuation device 74 to cause theactuation device 74 to not actuate the compression device 26.

The synchronization device 82 may be a computer that has a processor anda memory in some exemplary embodiments. The synchronization device 82may be a part of the cardiac monitoring device 80, actuation device 74and/or compression device 26 in accordance with various exemplaryembodiments. The synchronization device 82 may simply be a portion ofone of these components 80, 74 and/or 26 that syncs the formation andremoval of the compressive force with the cardiac cycle as desired. Thesynchronization of the application and removal of compressive force 72causes the areas of compression 23 to dynamically restrict blood flowthrough the carotid arteries 16 which leads to transient interruption ofcarotid blood flow. Although a single cardiac monitoring device 80,synchronization device 82, and actuation device 74 are shown any numberof these devices may be present in system 70 in other exemplaryembodiments.

The degree of the residual pressure in the expandable members 27, 46, 32during cardiac relaxation may vary depending on the adequacy of thediastolic cerebral blood flow. The divergence of cerebral emboli 17 andprevention of stroke throughout multiple cardiac cycles and for anextended period of time can be achieved through a noninvasive, safemethod that involves external compression of the carotid arteries 16 atthe time of cardiac systole and decompression during diastole. For shortperiods of time (that may be longer in patients under hypothermia) bothsystolic and diastolic restriction of the carotid flow can be achieved.As such, the areas of compression 23 may be formed, during all phases ofthe cardiac cycle for any length of time as may be desired. In theseinstances, there is not a dynamic cycling of the carotid artery 16compression, but rather a static continuous compression of the carotidarteries 16 at the areas of compression 23.

The extent and timing of actuation of the compression device 26 can varydepending on the variations of cardiac pathology and physiology. Thesystem 70 may be arranged with an option to delay, accelerate, prolongor shorten the length and intensity of the compressive force 72 with theresulting goal of minimizing the degree of cerebral embolization whileassuring adequate cerebral perfusion with the minimal trauma to theunderlying structures that are compressed. Although described as beingpulsated in a dynamic fashion based upon the cardiac cycle, or in astatic fashion irrespective of the cardiac cycle, the system 70 can bearranged so that both of these methods are employed. For example,certain ones of the expandable members 27, 32, 46 may be pressurized tocause consistent static forces on the carotid arteries 16 while othersones of the expandable members 27, 32, 46 may be dynamically pulsated insync with the carotid cycle. In some embodiments, one of the carotidarteries 16 can be statically compressed, and the other carotid artery16 can be cyclically compressed. The ability to use both static anddynamic, cyclical compression may allow achievement of optimalindividual regime of alteration of the cerebral blood flow.

The system 70 may also include an emboli monitoring device 84 that canmonitor the heart 11, aortic arch 12, carotid arteries 16 or any otherportion of the circulatory system for the presence of emboli 17, 18, 20.The emboli monitoring device 84 is shown in communication with thesynchronization device 82, but may be in direct communication with theactuation device 74 or compression device 26 or any other portion of thesystem 70 in other arrangements. The emboli monitoring device 84 upondetection of the appearance of potential emboli 17, 18, 20 in the heartcavities or other portions of the circulatory system may send thisinformation to the synchronization device 82 (or other component towhich it is in communication) which then causes the compression device26 to actuate via the actuation device 74. The initiation of thecompressive force 72 may be continued in a cyclical nature as previouslydiscussed, or may be static in nature in that the compressive force 72is applied through all phases of the cardiac cycle. The embolimonitoring device 84 may be trans-cranial Doppler ultrasound, carotidDoppler study, and/or transesophageal echocardiography. Further, theemboli monitoring device 84 may be the same type of device or method asdisclosed herein with respect to the cardiac monitoring device 80. Incertain exemplary embodiments, the emboli monitoring device 84 and thecardiac monitoring device 80 are the same device and are not separatedevices.

Although described as automatically starting the compressive force 72when emboli 17, 18, 20 are discovered by the emboli monitoring device84, it may be the case that instead of automatically starting thecompressive force 72 the health care professional is given the option ofmanually starting the compressive force 72. An alarm can be triggeredthrough sensing of the emboli monitoring device 84 and the health careprofessional may decide to begin the compressive force 72 if desired.

The system 70 can be arranged so that all of the functions of thecardiac monitoring device 80, synchronization device 82, embolimonitoring device 84, and actuation device 74 are performed by a singledevice 86 as shown for example in FIG. 16. Here, a processor and amemory may be included in the single device and the various functions ofthe aforementioned devices 80, 82, 84, and 74 can be executed by theprocessor, memory, sensors, and pump of the single device 86. In otherarrangements, one or more of the various devices 80, 82, 84 and 74 canbe separate from the single disclosed device 86 but in communicationtherewith. The compression device 26 may be actuated and releasedthrough communication with the single device 86. The compression device26 may be attached to the actuation device 74 portion of the singledevice 86.

A method for reducing or eliminating stroke during a surgical proceduremay first involve a brief compression of the carotid arteries 16 toensure adequate placement of the compression device 26. This can beconfirmed by carotid Doppler, a pressure gauge, percutaneous oximetry,transcranial Doppler, or other method. This compression process issynchronized with the cardiac cycle by means of EKG, pressure waveform,pacing, oximetry, Dopplerography, echocardiography or other ways ofcardiovascular monitoring. The process implements the idea of increasingthe compression of the carotid arteries 16 when the heart 11 is ejecting(systole) and decreasing it when the heart 11 is relaxing (diastole).

Once proper positioning is confirmed, the compressive force 72 may bereleased and carotid blood flow can be confirmed if desired. The cardiacsynchronization mode of function of the system 70 is initiated where theactuation of the compression device 26 is triggered by theelectrophysiological, mechanical, or other indices of the cardiac cycle.The systolic pressurization and diastolic relaxation of the compressiondevice 26 is then started for a period of time necessary for completeclearance of the heart 11, its structures and aorta 12 from allpotential emboli (usually, between 45 and 360 cardiac cycles). The wholeprocess can be repeated any time and on multiple occasions when thepossibility of the residual or newly formed intra-cardiac orintra-aortic emboli 18 is anticipated. It is therefore the case that thecompression device 26 cycles to cause compressive forces 72 and toremove compressive forces 72 to compress and release compression fromthe carotid arteries 16 a plurality of times over and over again. Duringthe times that the carotid arteries 16 are not being compressed,generally during the diastole phase, blood flow may go through thecarotid arteries 16 and into the brain. Blood flow may thus go to thebrain with the risk of emboli 17 being transferred to the brain small ornon existent.

Should the emboli monitoring device 84 (i.e. cardiac ECHO, vascularDoppler ultrasound, pulse oximetry, trans-cranial Doppler,echocardiography, arterial Doppler ultrasound, cerebral oximetry, orother) detect the presence of particulate material in the heart 11chambers, ascending aorta 12 or cerebral arteries an alarm would go offwith an option of automatic re-initiation of the process of synchronizedcarotid compression. The pressure would be released during diastole toavoid undue interruption of the cerebral flow. The alarm, deflation and,if needed, inflation could be overridden by the physician whenclinically indicated. Moreover, the duration of compression may extendthrough several cardiac cycles if indicated.

The timing of the carotid compression in relation to the phases of thecardiac cycle may vary from making the duration of compression orrelaxation of the expandable components of the compression device 26equal to, shorter or longer than the duration of systole and diastole.In some arrangements, the compressive force 72 may be applied at alltimes during the systole phase, and removed at all times during thediastole phase. The systole phase may be broken up into an early portionand a remaining portion. In the early portion of the systole phase theheart 11 may not yet be ejecting blood or emboli 20. Here, the chance ofdirecting emboli 17 through the carotid arteries 16 is minimal.Compressive force 72 may not be applied during the diastole phase andthe early systole phase, but may be applied during the remaining portionof the systole phase.

The compressive force 72 may be strong enough to completely close thecarotid arteries 16, or may only partially close the carotid arteries16. In some arrangements of the system 70, removal of the compressiveforce 72 is complete removal such that there is no compression of thecarotid arteries 16. In other embodiments, removal of the compressiveforce 72 is partial removal such that some compressive force remains onthe carotid arteries 16 but not the full amount of the compressive force72. In these arrangements, the carotid arteries 16 may be compressedsome degree even when the compressive force 72 is removed.

The alarm system 59 may be included with the system 70 and can be aseparate component or may be incorporated into one of the disclosedcomponents of the system 59. The alarm system 59 may be in communicationwith one of the components of the system 70 or may not be incommunication with any of the aforementioned components of system 70.The alarm system 59 may sound an alarm if the compression of the carotidarteries 16 is performed for a certain amount of time, of if there isevidence of the detection of potential emboli 18, 20 via the embolimonitoring device 84.

The system 70 may also monitor the indices of the carotid and cerebralcirculation during the compression of the carotid arteries 16 and duringthe times in which the carotid arteries 16 are not compressed. Thismonitoring may be performed by one of the components or methodspreviously disclosed with respect to the devices 80, 82, 84, 59 or 74,or may be performed by a separate device or method.

While the present invention has been described in connection withcertain preferred embodiments, it is to be understood that the subjectmatter encompassed by way of the present invention is not to be limitedto those specific embodiments. On the contrary, it is intended for thesubject matter of the invention to include all alternatives,modifications and equivalents as can be included within the spirit andscope of the following claims.

What is claimed:
 1. A system for use in prevention of stroke,comprising: a compression device that is a neck collar configured forbeing positioned around a neck of a patient for applying bilateralcompressive force to first and second carotid arteries, wherein thecompression device is adjustable so as to apply the compressive forceand so as to not apply the compressive force, wherein the compressiondevice has a first expandable member configured for applying thecompressive force to the first carotid artery, wherein the compressiondevice has a second expandable member configured for applying thecompressive force to the second carotid artery, wherein the firstexpandable member and the second expandable member are external to thepatient; an actuation device for causing the compression device to applythe compressive force, wherein the compressive force is applied tocreate an arterial pressure gradient sufficient to limit or preventemboli from entering cerebral circulation, wherein the actuation deviceis structured to result in the compressive force to the first carotidartery and the second carotid artery to be dictated by both of thefollowing bounds: a minimum of 70 mm of Hg of absolute pressure; andexceeding an arterial pressure of a patient by at least 10 mm of Hg; andwherein the compression device has a connecting tube that places thefirst expandable member into fluid communication with the secondexpandable member such that the first and second expandable membersexpand at the same time; wherein the connecting tube extends from anoutlet of the first expandable member to an inlet of the secondexpandable member and is in isolation to be in fluid communication withonly the first expandable member and the second expandable member, andwherein fluid is transferred into the first expandable member from apressure tube and is subsequently transferred through the connectingtube to the second expandable member; and wherein the neck collar has acentral axis that is located within a cavity defined by the neck collarextending 360 degrees around the central axis wherein the central axisis free from engagement with the neck collar such that the central axisextends in a direction parallel to a direction of extension of the firstand second carotid arteries, and wherein the central axis is arrangedrelative to the first and second expandable members such that thecompressive force applied by the first and second expandable member isoriented at an angle of 90 degrees to the central axis, and wherein avertical direction extends in a direction parallel to the central axis,wherein upon expansion of the first and second expandable members thefirst and second expandable members increase in length in the verticaldirection.
 2. The system as set forth in claim 1, wherein the first andsecond expandable members have walls with a strength capable ofwithstanding 70 mm of Hg of pressure, wherein the compression device hasa strap that has a hook and loop fastener to effect attachment of thecompression device to the neck of the patient.
 3. The system as setforth in claim 1, wherein the compressive force is of such a degree thatthe first and second carotid arteries are compressed to such an extentthat blood flow through the first and second carotid arteries iscompletely stopped.
 4. The system as set forth in claim 1, wherein theneck collar wraps 360 degrees around the neck of the patient when theactuation device causes the compression device to apply the compressiveforce.
 5. The system as set forth in claim 1, wherein the compressiondevice has a first insertion pocket into which the first expandablemember is disposed, and wherein the compression device has a secondinsertion pocket into which the second expandable member is disposed. 6.The system as set forth in claim 1, further comprising an alarm systemthat produces an alarm that is triggered when the compressive forceapplied to the first carotid artery exceeds a preset magnitude ofcompressive force and/or the time of compression exceeds 90 seconds. 7.The system as set forth in claim 1, wherein when the compressive forceis applied there is some amount of compression of the first carotidartery and the second carotid artery, and wherein when the compressiveforce is not applied there is no compression of the first carotid arteryand the second carotid artery.
 8. The system as set forth in claim 1,wherein the actuation device is a pressure source that delivers a fluidthat is air to the compression device, wherein the first and secondexpandable members receive the air from the pressure source, wherein thefirst and second expandable members are expanded by the air and thecompressive force is applied when the first and the second expandablemembers are expanded.
 9. A system for use in prevention of stroke,comprising: a compression device for applying bilateral compressiveforce to first and second carotid arteries, wherein the compressiondevice is adjustable so as to apply the compressive force and so as tonot apply the compressive force, wherein the compression device has afirst expandable member configured for applying the compressive force tothe first carotid artery, wherein the compression device has a secondexpandable member configured for applying the compressive force to thesecond carotid artery, wherein the first and second expandable membershave walls with a strength capable of withstanding 70 mm of Hg ofpressure; and an alarm system that measures the time of application ofthe compressive force to the first and second carotid arteries, whereinthe alarm system measures the magnitude of the compressive force appliedto the first and second carotid arteries, wherein an alarm is triggeredby the alarm system if the time of application of the compressive forceto the first and second carotid arteries exceeds a set amount of time,and wherein the alarm is triggered by the alarm system if the magnitudeof compressive force applied to the first and second carotid arteriesexceeds a set amount of magnitude of force; wherein the compressiondevice is structured to result in the compressive force to the firstcarotid artery and the second carotid artery to be dictated by both ofthe following bounds: a minimum of 70 mm of Hg of absolute pressure; andexceeding an arterial pressure of a patient by at least 10 mm of Hg; andan emboli monitoring device that detects the presence of emboli, whereinthe compression device initiates application of the bilateralcompressive force to start compression of the first carotid artery andthe second carotid artery upon being triggered by the detection of thepresence of the emboli by the emboli monitoring device.
 10. The systemas set forth in claim 9, wherein when the alarm is triggered by thealarm system, the alarm system is configured to cause the compressiondevice to be adjusted so as to not apply the compressive force.
 11. Thesystem as set forth in claim 10, wherein when the alarm is triggered bythe alarm system a manual override is activated to prevent the alarmsystem from causing the compression device to be adjusted so as to notapply the compressive force.
 12. The system as set forth in claim 9,wherein the compression device is configured as a neck collar that wraps360 degrees around the neck of the patient.
 13. The system as set forthin claim 10, wherein the compression device has a first insertion pocketinto which the first expandable member is disposed, and wherein thecompression device has a second insertion pocket into which the secondexpandable member is disposed.
 14. A system for use in prevention ofstroke, comprising: a compression device for applying bilateralcompressive force to first and second, carotid arteries, wherein thecompression device is adjustable so as to apply the compressive forceand so as to not apply the compressive force, wherein the compressiondevice is configured as a neck collar that wraps 360 degrees around theneck of the patient, wherein the compression device has: a strap that isconfigured for holding the compression device to the neck of thepatient; a first compression member configured for applying thecompressive force to the first carotid artery, wherein the firstcompression member is non-expandable; a second compression memberconfigured for applying the compressive force to the second carotidartery, wherein the second compression member is non-expandable; anactuation device for causing the compression device to apply thecompressive force, wherein the compressive force is applied to create anarterial pressure gradient sufficient to limit or prevent emboli fromentering cerebral circulation, wherein the actuation device is selectedfrom the group consisting of a linear actuator, a motor, and a lock andadjustment clip; and an alarm system, wherein when an alarm is triggeredby the alarm system, the alarm system is configured to cause thecompression device to be adjusted so as to not apply the compressiveforce; a manual override configured to be activated to override thealarm system's deactivation of the compressive force upon triggering ofthe alarm system so that the manual override causes the compressiveforce to be continued to be applied.
 15. The system as set forth inclaim 14, wherein the first compression member and the secondcompression member are made of foam that is compressible.
 16. The systemas set forth in claim 15, wherein the alarm system measures the time ofapplication of the compressive force to the first and second carotidarteries, wherein the alarm system measures the magnitude of thecompressive force applied to the first and second carotid arteries,wherein the alarm is triggered by the alarm system if the time ofapplication of the compressive force to the first and second carotidarteries exceeds a set amount of time, and wherein the alarm istriggered by the alarm system if the magnitude of compressive forceapplied to the first and second carotid arteries exceeds a set amount ofmagnitude of force.
 17. A system for use in prevention of stroke,comprising: a compression device for applying bilateral compressiveforce to first and second carotid arteries, wherein the compressiondevice is adjustable so as to apply the compressive force and so as tonot apply the compressive force, wherein the compression device has afirst expandable member configured for applying the compressive force tothe first carotid artery, wherein the compression device has a secondexpandable member configured for applying the compressive force to thesecond carotid artery, wherein the first and second expandable membershave walls with a strength capable of withstanding 70 mm of Hg ofpressure; and an alarm system that measures the time of application ofthe compressive force to the first and second carotid arteries, whereinthe alarm system measures the magnitude of the compressive force appliedto the first and second carotid arteries, wherein an alarm is triggeredby the alarm system if the time of application of the compressive forceto the first and second carotid arteries exceeds a set amount of time,and wherein the alarm is triggered by the alarm system if the magnitudeof compressive force applied to the first and second carotid arteriesexceeds a set amount of magnitude of force; wherein the compressiondevice is structured to result in the compressive force to the firstcarotid artery and the second carotid artery to be dictated by both ofthe following bounds: a minimum of 70 mm of Hg of absolute pressure; andexceeding an arterial pressure of a patient by at least 10 mm of Ng; andwherein when the alarm is triggered by the alarm system, the alarmsystem is configured to cause the compression device to be adjusted soas to not apply the compressive force; a manual override configured tobe activated to override the alarm system's deactivation of thecompressive force upon triggering of the alarm system so that the manualoverride causes the compressive force to be continued to be applied. 18.A system for use in prevention of stroke, comprising: a compressiondevice for applying bilateral compressive force to first and secondcarotid arteries, wherein the compression device is adjustable so as toapply the compressive force and so as to not apply the compressiveforce, wherein the compression device has a first expandable memberconfigured for applying the compressive force to the first carotidartery, wherein the compression device has a second expandable memberconfigured for applying the compressive force to the second carotidartery, wherein the first and second expandable members have walls witha strength capable of withstanding 70 mm of Hg of pressure; and an alarmsystem that measures the time of application of the compressive force tothe first and second carotid arteries, wherein the alarm system measuresthe magnitude of the compressive force applied to the first and secondcarotid arteries, wherein an alarm is triggered by the alarm system ifthe time of application of the compressive force to the first and secondcarotid arteries exceeds a set amount of time without regard as towhether emboli are or are not detected by an emboli monitoring devicesuch that this triggering causes the alarm system to remove applicationof the compressive force to the first and second carotid arteries, andwherein the alarm is triggered by the alarm system if the magnitude ofcompressive force applied to the first and second carotid arteriesexceeds a set amount of magnitude of force; wherein the compressiondevice is structured to result in the compressive force to the firstcarotid artery and the second carotid artery to be dictated by both ofthe following bounds: a minimum of 70 mm of Hg of absolute pressure; andexceeding an arterial pressure of a patient by at least 10 mm of Hg.